docs: def convert_npdist(self, node):
          """
          Convert the given node into a Nodal Plane Distribution.
  
          :param node: a nodalPlaneDist node
          :returns: a :class:`openquake.hazardlib.geo.NodalPlane` instance
          """
          with context(self.fname, node):
              npdist = []
              for np in node.nodalPlaneDist:
                  prob, strike, dip, rake = (
                      np['probability'], np['strike'], np['dip'], np['rake'])
                  npdist.append((prob, geo.NodalPlane(strike, dip, rake)))
              if not self.spinning_floating:
                  npdist = [(1, npdist[0][1])]  # consider the first nodal plane
              return pmf.PMF(npdist)